Recently, an organic light-emitting display panel used as a flat panel display, which is a light-emitting device itself, is greatly concerned by more and more people. The organic light-emitting display panel is realized through an Organic Light-Emitting Diode (OLED) disposed on a substrate. The lifetime of the OLED device is not only dependent on selected organic material but it is also dependent on a method for packing the device. As for an organic electronic device, in particular the OLED, it is not desired for oxygen and moisture from the ambient to enter into inside of the device to contact the sensitive organic medium and electrodes. That is because the property of the OLED device is easily degraded or invalidated due to the existence of the oxygen and moisture inside the OLED device, and even a tiny amount of moisture will cause an organic compound layer and an electrode layer to be peeled off, thereby producing a black speck. As a result, in order to restrain the degradation and invalidation of the OLED device during a long term operation process and run stably to reach a sufficient lifetime, block performance of the package material is greatly desired. Nowadays, a method of etching a glass shield or a metallic case is commonly adopted to cover an organic light-emitting portion, and the sealant is applied around the organic light-emitting portion and an absorbent for absorbing the moisture is placed therein so as to guarantee the oxygen and moisture not to close to the organic medium or guarantee the oxygen and moisture to be absorbed by the absorbent before reaching the organic medium, thereby ensuring the lifetime of the organic light-emitting. However, the sealed case has a relative large quality such that the whole dimension of the device is thickened accordingly, which in not in conformity with the light and thin requirements. In addition, the metal is also not suitable for some application due to its opaqueness. Therefore, in order to make the organic light-emitting display panel lighter and thinner, it is necessitated to eliminate the spaces occupied by the absorbent for absorbing the moisture and the glass/metallic case. Based on this, more and more researchers pay their attention to a thin film package. In the thin film package, in order to limit or prevent the invasion of the oxygen and moisture, the package structure is generally configured as a stack of multiple-layer thin films.
The package thin film is often adopted in a manner of a stack of an non-organic film layer and an organic film layer, the dense non-organic film layer blocks water and oxygen, the thicker and soft organic film layer covers the steps on a surface and impurity to relieve pressure. A photomask is needed to pattern the thin film package during a process of forming the film, and the region used for binding IC and cutting is exposed.
The material of the organic film layer has s worse performance of blocking water and oxygen, and cannot be directly exposed in the air. Therefore, it is necessitated to ensure the non-organic firm layer to cover the organic film layer. Currently, the existing corresponding manner is to enlarge the design value of the coverage area covered by the non-organic firm layer, guaranteeing the organic film layer to be entirely covered inside the non-organic firm layer. This method has at least following defects:
1. Although it is guaranteed that the organic film layer is entirely covered inside the non-organic firm layer by enlarging the design value of the coverage area of the non-organic firm layer, the existence of an extended region will lead to an increase in the coverage area of the non-organic firm layer. In addition, the non-organic firm layer itself has a certain extended effect, so that an invalid region located at the periphery of the device is enlarged ultimately, thereby it is not advantageous to a design of narrow frame of the organic electroluminescence.
2. The material of the organic firm layer has a low capability of blocking water and oxygen, even has a capability of absorbing water and oxygen. In terms of the package design of the thin film, it is required that the non-organic firm layer has a coverage area larger than a coverage area of the organic firm layer. However, the precursor of the organic firm layer is generally formed by a liquid material, and the flow of the liquid material is uncontrollable in a certain degree, the extended length of any of positions located at the periphery of the device are not all same as each other, and the fluctuation of the distribution strengths when the thickness of the organic firm layer becomes larger and larger. It is not guaranteed that the organic firm layer is covered efficiently only by relying on the fixed design value of the non-organic firm layer, and the requirement of blocking water and oxygen of the electroluminescence device is unreachable.
FIG. 1 is a cross-sectional view showing an organic light-emitting display panel in the related art. As shown in FIG. 1, U.S. Pat. No. 8,664,649 B2 discloses an empirical formula for an extended length of an organic film layer, where L1 represents the first diameter of the deposition region of an organic film layer 30, L2 represents the second diameter of the non-organic film deposition area, D represents a thickness of the organic film layer in a unit of μm, M represents a dimension of an invalid region caused by the extended portion 31 of the organic film layer:M=171D+138.14 μm
Normally, the height of the impurity occurring at a surface of the OLED device is about in a range of 2 to 4 μm, if it is supposed that the organic film layer has a 5 μm in thickness, M=171*5+138.14 μm=993.14 μm.
Then, an coverage area of the non-organic film layer 40 is needed to be larger than 993 μm, and the length of the invalid area located at the left side and right side of the display region is at least larger than 2 mm(0.993 mm*2), which is not advantageous for the narrow-frame design of the organic light-emitting display panel.